Inuit diet and vitamin C

#1

Curious what others think about this relatively recent paper, suggesting algae was an important source of vitamin C in the Inuit diet. In other words, they did not get all the nutrients they needed solely from animal food

Keto or Carnivore?
#2

It was interesting to me :slight_smile: And it makes sense.

(Bacon is a many-splendoured thing) #3

I don’t recall Stefansson’s mentioning algae in the the Inuit diet.

But people can’t seem to wrap their heads around the idea, known for centuries, that fresh meat prevents scurvy. The problem that led the British Navy to supplement their sailors’ diet with limes and lemons was not that they didn’t know about fresh meat, but that keeping livestock on board a cramped wooden sailing ship on long deployments was impossible. Much easier to store some citrus fruit.

Whether there’s something about fresh meat that reduces or eliminates our need for Vitamin C, or whether meat actually contains Vitamin C is not something that ever seems to get looked into. The assumption that meat doesn’t contain that particular vitamin is so ingrained in people’s minds that no one ever actually looks for it. The U.S. Department of Agriculture’s food composition database just says “assumed zero.”

#4

We know meat alone is enough for vitamin C for many people but obviously if plant is available in the north, people eat that too.
The article brought up very valid things like cooking lowers vitamin C content and mere muscle meat contains little of it to begin with. And that things like eyes may contain more but a seal only have 2 tiny ones.

I didn’t fully understand why they acted like 1 kg meat would be much though. Even I could and would eat that much if I had no many other options and would be in need…

So, when one needs vitamin C, they should use whatever they have if the base food contains little. Still makes perfect sense to me.

And I feel good about my carnivore-ish (many of the items I add in tiny amounts have a serious vitamin C content). I probably never will have scurvy (and if I do, that will have nothing to do with my chosen woe, it would happen in severe unwilling starvation). My meat is very well-cooked most of the time and I like that I needn’t to think about this potential problem.
But the article says they calculated with 50% vitamin C loss when the meat was cooked. If true, it’s good news as I really depend on my meat intake regarding vitamin C when I am very close to carnivore. Eggs and dairy don’t have it as far as I know. And my plant matter is tiny, maybe it barely helps… Never calculated it. I would notice if my body lacked something as important as vitamin C and I just trust other people’s experiences and my tiny knowledge until then.
And if the tiny plant matter didn’t make the vitamin C need of inuits higher, they probably won’t do it to me either… It would be a bit illogical evolution wise I suppose…

#5

Out of interest, do we know if it takes into account Ely’s glucose-ascorbate antagonism theory (which is that glucose and ascorbic acid use the same pathway)?

The idea is that if glucose isn’t present, less vitamin C is required to avoid a deficiency because more of it is absorbed.

So maybe that’s a factor? If the paper is written from the perspective of what a carb eater requires to achieve the optimal vitamin C level, then maybe it would appear that algae is absolutely required to hit that level - when maybe a lower level might be sufficient in that food environment?

#6

Read the paper. It’s a fun read — not overly technical. The 1930s scientists measured vitamin C in the various meats and the algae that was eaten by the people they were studying (see Table 2). They also determined vitamin C loss with cooking (about 50%)

(Bacon is a many-splendoured thing) #7

It could very well be. Do you have a citation I could check out? This sounds interesting.

(Bacon is a many-splendoured thing) #8

I’ll read it, as soon as I have a moment.

(Ohio ) #9

That’s Dr. Shawn Bakers thought process. The molecules are similar. Works for me.

#10

I’m pretty confident I first came across it on Paleo Medicina: https://www.paleomedicina.com/hu/vitamin_c_and_disease_insights_from_the_evolutionary_perspective

7. The glucose-ascorbate antogonism theory
The glucose-ascorbate antagonism (GAA) theory was first proposed by John Ely as early as the 1970s [3]. The theory postulates that given the structural similarity between glucose and vitamin C, the two molecules compete for same transport system to enter cells [10]. It has been shown that cellular uptake of both AA and DHAA may be competitively antagonized by elevated glucose levels. Specifically, AA uptake by the small intestine enterocytes was shown to be inhibited by elevated glucose concentration [9]. DHAA transport into cells was shown to be impaired by high blood glucose concentration in most cell types including adipocytes, erythrocytes, granulosa cells, neutrophils, osteoblasts and smooth muscle cells [10].

I couldn’t find a lot when looking for his original work on PubMed, but I did find this writing from him: http://orthomolecular.org/library/jom/1996/articles/1996-v11n01-p023.shtml

In 1973, we had already deduced and related to Linus Pauling a theory called the “Glucose Ascorbate Antagonism”. It argued that the clinical trials of ascorbic acid (AA) against colds and cancer may have failed because of the high blood sugar levels in the affluent nations. Essentially, this theory can be stated in three parts.

(1) Certain cell types normally have intracellular ascorbic acid (AA) levels that are “pumped up”, largely by insulin and another process, resulting in vastly higher AA levels than plasma in the surrounding blood (approximately 50 times higher in leukocytes and 300 or so in fetal cells). This is especially true if the BG level is in the low range that was normal until the 1900s and is still seen today where the primitive diet prevails. (2) The high AA levels in such cells are necessary to drive the HMP shunt (or pentose pathway) needed for some normal functions, including mitosis, phagocytosis, etc. (3) “Modest” BG elevations (≈ 50%, common after western diet meals) competitively inhibit insulin-mediated active transport of AA into these cells, resulting in low intracellular AA levels, low HMP shunt, and cell dysfunction. Leukocytes, therefore, do not respond to mitogen, attack tumors or pathogens, etc. (in CMI), or remove thrombi in vascular disease, and fetal cells divide too slowly.

And also this article by him: https://arxiv.org/ftp/physics/papers/0403/0403023.pdf

Three decades ago, after reading the Bowman-Gray 1971 report, we deduced and related to Linus Pauling a theoretical reason for the failure of clinical trials of AA
against colds and cancer—the high blood glucose levels in developed nations. This theory is called “Glucose-Ascorbate Antagonism” (GAA). We extended this theory experimentally and obtained supporting findings in aging, birth defects, cancer, infectious diseases, and others (Ely 1981, 1996a,b; Santisteban et al 1985; Hamel et al 1986; Ely et al 1988; Ely and Krone 2002,a,b; Krone and Ely 2001, 2004) (see Section 3 below). A very high world wide correlation of cancer incidence with sugar consumption has been reported (Hems 1978; Carroll 1977; Michaud et al 2002; Nilsen and Vatten, 2001; Schoen et al 1999; Augustin et al 2003). Our theory, supported by human and animal studies, suggests that the most common factor increasing tumor tolerance in developed nations is the gross elevation of mean blood glucose (Sanisteban et al 1985; Ely 1996a). A prominent example of the diseases of affluence is the estimate that about one-fourth of those alive today in these nations will present with clinical cancer during their lifetime. The GAA predicts that such individuals can be identified approximately as the older half of the upper half by sugar consumption. The basis for this prediction can be seen in two more statistics of the affluent societies: (1) ~30 times more cancer occurs above age 55 than below 35; and (2) the 2-hour value on glucose tolerance tests rises 10% per decade of age (Ely 1996b; Ely and Krone 2002a).
We sometimes think of the HMS as paradoxical because its rate varies inversely with the concentration of its substrate, glucose. The GAA is important in the normal (low-dose) range of ~10 g/day or less AA. The theory states that the intracellular AA levels in certain cell types, such as leukocytes and fetal cells, are ‘pumped up’ by insulinmediated active transport to the measured concentrations, ~50 times higher than in the surrounding plasma. This increase of intracellular AA occurs effectively if blood glucose is in the low range—50 to 90 mg/deciliter (mg/dL). This blood sugar was considered normal until the 1900s and is still seen where a primitive (unrefined) diet prevails, but it is approximately half the glycemic levels typical of affluence (Ely 1996a; Chatterjee and Bannerjee 1975).

It’s an interesting theory and the conclusion of Zsofia Clemens’ work gives a useful recap:

From the prospective cohort and correlational studies it is clear that higher blood level of AA is associated with lower mortality and morbidity in several chronic conditions. At the same time, high-grade evidence from clinical intervention studies indicate that vitamin C taken as a supplement provide little or no benefit in the prevention or treatment of chronic diseases. Indeed, apart from intervention studies of common cold where minor benefit was reported, no single RCT is available that found a clinically meaningful benefit in hard clinical endpoints of chronic diseases including cancer and cardiovascular diseases. We put forward that the discrepancy between correlational and interventional studies, as regards the role of vitamin C, is only apparent and may be resolved by introducing the GAA theory. As detailed above, metabolism of vitamin C, including absorption and its uptake by several cell types, is inhibited by increasing glucose concentration. Western type diets resulting in carbohydrate overconsumption and high blood level of glucose may inhibit utilization of vitamin C also when taken as a supplement.

Edit: And I say that my PubMed searches failed, but this biography of him suggests that this work on the GAA was peer reviewed: https://isom.ca/profile/john-ely/

Because of his satellite cosmic ray research and interest in the mutagenic burden of the penetrating background radiation and its possible role in aging and neoplastic initiations, he found statistically significant latitude dependence in cancer mortality. The background radiation decreases at low latitudes and cancer deaths appeared to exhibit the same trend, except for a few low latitude countries whose high mortalities violated this expectation. From WHO data, he found that those countries had high sugar/refined carbohydrate consumption. Using this data and two discoveries on leukocytes, he deduced the glucose ascorbate antagonism theory (GAA). In 1973, John related to Linus Pauling a theoretical reason why the clinical trials of vitamin C against colds and cancer may have failed because of the high blood sugar levels in the affluent nations. The GAA was described in over a dozen peer reviewed publications, as well as, several articles in the Journal of Orthomolecular Medicine . These articles show how GAA has relevance to infectious diseases, atherosclerosis, birth defects, cancer and aging.

#11

Interesting ideas, but they need to be tested. Relatedly, Pauling and his colleagues believed that huge amounts of vitamin C had health benefits. Amounts thousands of times greater than you could get even if eating fruits and vegetables. So, if you cite their work, seems also useful to consider the context — which is not a low vitamin C intake diet.

Vitamin C plays so many roles in the body (collagen synthesis, wound healing, possibly preventing oxidation of LDL), I personally would not take the chance of a deficiency.

#12

Yes, the papers I linked explain this - their work wasn’t in the context of a low ascorbic acid intake, but was focused on their confusion as to why high supplementation of ascorbic acid didn’t yield the positive results they anticipated.

Still, the mechanism of high blood glucose preventing the absorption of ascorbic acid that they discovered could be a potential explanation for what are perceived to be discrepancies in other studies. It would be useful to have some full studies on the topic.

#13

No on the importance of it at all. Not important in that the dietary use of big meat/big fat from their hunting etc. covered entire amt of Vit. C they required for life survival. So this ‘needed and importance’ factor is not a real deal issue for me ever in that.

One thing needed by the physical body for total survival. Protein and fat. Provides it all, obviously meat protein trumps plant protein every single time so…with that as the base, the importance factor is mute.

now that is not to say they did not take advantage of fireweed, berries if they could get them in season or any other plant matter on the land or sea that was acceptable for daily life as they could get their paws on ‘food’ in their environment. But to put big importance on gnawing down seaweed daily for ‘their vitamin C intake’, nope.

key also being we are talking those in an environment of ‘survival’ vs. grocery store shopping with meat on the table every night. No kill in the hunt. No food, so of course they are sourcing out ANY other forms of edible they can for survival. So in a way the whole ‘they ate’ can’t ever be compared to ‘our lives of today’ in any way.

If my hunts went bad for weeks on end, darn right I would be gnawing down seaweed LOL

#14

This part might shed light:

According to Høygaard et al., severe scurvy was unknown in the area under study, but sub-scurvy cannot be excluded in view of the chronic gingivitis observed by Høygaard et al. in the spring. Høygaard et al. performed 34 blood determinations of vitamin C, 18 between November and April, and 16 between July and August. In total 12 (35%) observations were between 0.5 and 1.2 mg.dl−1, 16 (47%) around 0.4 mg.dl−1 and 6 (18%) less than 0.3 mg.dl−1. The reported vitamin C blood determinations reflect hypovitaminosis C for 47% of the sample, and scurvy levels for 18% of the population. Despite the fact that, according to Høygaard et al., clinical scurvy was not present, and probably not observed by early explorers, but it is highly probable that Inuit with a traditional nutrition lived on the edge of scurvy. It is remarkable that all 6 with extreme low blood concentrations of vitamin C, lived near the trading centre consuming more imported food and less traditional food.

There might be something to the hypothesized interaction between glucose and ascorbate absorption, but Haygaaerd’s observations suggest that it would be an issue even in the context of the very low carb Inuit diet.

#15

What do you think of Høygaard’s original findings? https://www.nature.com/articles/143943a0

There’s some parts in the original that seem to have been omitted in the reanalysis.

#16

I’m only seeing a summary page on the link. It references a future book but I don’t see a link to this. What is missing?

#17

I don’t know if a book eventuated; most of the articles that cite the work use this link.